Here are some of the topics and ideas you'll find in Part II, Chapter V, of Gaudium et Spes.
Chapter V – Fostering of Peace and Establishment of a Community of Nations
* Today's world is marked with hardship, anxiety, and war.
* But a “truly human world” requires a worldwide commitment to true peace.
Nature of Peace
* Peace is not merely a balance of power but the fruit of a “right ordering of things.” Such a just order is designed by God.
* Peace “derives from the eternal law” and is built up gradually through “constant effort” and mutual relationships.
* Peace is ultimately the “fruit of love” and flows from the peace of Christ, Who is the Prince of Peace.
* Christians have the responsibility to “speak the truth in love,” to plead for peace, and to work to bring it about.
* War is the result of sin and can only be overcome by love.
Section 1: Avoidance of War
Curbing the Savagery of War
* Modern warfare is more savage than ever, and war is more complex due to the “intricacy of international relations.”
* Natural law and conscience must be the governing forces of any wars that break out. International conventions about treatment of civilians, the wounded, and prisoners must be strictly observed.
* Lawful self-defense is a possibility but only as a last resort and within tightly controlled limits.
* Modern weapons have “immeasurably magnified the horrors and wickedness of war” and go “far beyond the bounds of legitimate defense.”
* The Church condemns total warfare and all acts of war “directed to the indiscriminate destruction of whole cities or vast areas and their inhabitants.” These acts are crimes against God and humanity.
The Arms Race
* The arms race does not achieve peace. It only spreads aggression and anxiety.
* The arms race is “one of the greatest curses on the human race and the harm it inflicts on the poor is more than can be endured.”
* New approaches to resolving conflicts, reformed attitudes, and a better sense of responsibility are necessary to free the world from fear and bring peace.
Total Outlawing of War: International Action to Prevent War
* The ultimate goal of humanity should be a complete outlawing of war “by international agreement.”
* To achieve this goal, nations must agree on a “universally acknowledged public authority” to enforce laws, uphold security, and foster justice.
* All countries should strive to “put aside nationalistic selfishness and ambitions to dominate other nations” and adopt a respectful worldview.
* All people must participate in peace-making, changing their attitudes and their hearts as necessary to promote the security and development of the whole human race.
Section 2: Establishment of an International Community
Causes of Discord: Remedies
* Peace can be established only by rooting out the “causes of discord” that lead to war, including injustice, economic inequality, pride, distrust, envy, selfishness, hunger for power, and contempt for humanity.
* Organizations working for peace should be promoted to lessen and eliminate these causes of discord.
The Community of Nations and International Organizations
* International organizations should be developed to promote the “universal common good” and provide for human needs.
* Within these organizations, people can work together to solve problems, prevent wars, promote brotherhood, and build peace.
International Cooperation in Economic Matters
* Worldwide “cooperation in economic matters” is essential to decrease inequalities; promote education and resource development in poorer countries; and offer required material aid.
* The help wealthier countries give to poorer ones must be offered with a “spirit of generosity,” with respect, and without ulterior motives and agendas.
* Strong communication between nations and people is essential for proper cooperation.
Some Useful Norms
* Total human development is the goal for developing nations.
* Affluent nations must help developing nations meet their goal.
* The international community should be in charge of fairly distributing resources.
* The spiritual nature of humanity must be recognized and fostered along with economic and social structures.
* Population concerns must be addressed according to the divine moral law.
Role of Christians in International Aid
* Christians have the responsibility to work toward a just international order and true peace and to witness to a spirit of poverty and love that will help correct the imbalances and hardships of the modern world.
* Christians must always act with true generosity.
Effective Present of the Church in the International Community
* The Church is involved in building world-wide peace and fraternal communion among all people. She does this by teaching divine and natural law, preaching the Gospel, dispensing graces, and being present in all communities to serve.
* The Christian faithful have a responsibility to work toward peace in their own environments, cooperate with others, and train themselves and their young people.
Role of Christians in International Organizations
* Various “Catholic international bodies” should assist international organizations and work to form solidarity between all people.
* Catholics should cooperate as actively as possibility to foster love and justice for the poor,
Role of Individual Christians and of Local Churches
* In this document, the Council intends to help all people attain “a keener awareness of their own destiny, to make the world conform better to the surpassing dignity of man, to strive for a more deeply rooted sense of universal brotherhood, and to meet the pressing appeals of our times with a generous and common effort of love.”
* All of the proposals found in this document are based upon the Word of God and “the Spirit of the Gospel.”
Dialogue Between All Men
* Sincere dialogue between all people is necessary to foster true unity and still maintain “legitimate diversity.”
* The Church follows this principle: “let there be unity in what is necessary, freedom in what is doubtful, and charity in everything.”
* All people must work together to “build up the world in a spirit of genuine peace.”
A World to Be Built up and Brought to Fulfillment
* Christians have the task of embracing the Gospel, allowing themselves to be enriched by it, and joining other people to build up a world of true love and peace.
* When Christians recognize Christ in all people and bear witness to the truth, they share “the mystery of His heavenly love” with the whole world.